CN108461633A - A kind of hybrid and preparation method thereof for perovskite solar cell electron transfer layer - Google Patents

Abstract

The present invention relates to a perovskite solar cell electron transport layer that can be used for low temperature preparation and its preparation method. The present invention adopts solvothermal method to prepare titanium dioxide nano-dispersion liquid, and compound TiO2 _nano -dispersion liquid with alcohol-soluble conjugated polymer , the conjugated polymer/TiO ₂ hybrid material was prepared, and finally the conjugated polymer/TiO ₂ hybrid material was spin-coated on the plasma-treated ITO glass substrate by the spin coating method, and the conjugated polymer/TiO 2 hybrid material was prepared. The TiO ₂ hybrid film is the electron transport layer. The beneficial effect of the present invention is: the present invention provides the preparation method of the alcohol/water-soluble conjugated polymer that side chain contains carboxyl group or sulfonic acid group; Hybrid material for electron transport layer of titanium ore solar cell and preparation method thereof.

Description

A hybrid for electron transport layer of perovskite solar cells and its preparation method

technical field

The invention relates to the technical field of solar cells, in particular to an electron transport layer of a perovskite solar cell that can be prepared at low temperature and a preparation method thereof.

Background technique

Since the organic-inorganic hybrid perovskite material was first used in the field of optoelectronics in 2009, perovskite solar cells based on this material have attracted great attention because of the low cost and high energy conversion efficiency of perovskite solar cells. high. Perovskite solar cells are divided into two types of structures, which are mesoscopic structure and planar heterojunction structure. The earliest perovskite solar cell structure was a mesoscopic structure. Later studies found that perovskite materials have longer carrier diffusion lengths and longer carrier lifetimes, so perovskite materials can be used in planar heterojunction structures perovskite solar cells. Studies have shown that planar heterojunction perovskite solar cells with _TiO2 as the cathode buffer layer are easier to fabricate and can also achieve higher power conversion efficiency (PCE). However, a high-quality dense anatase _TiO2 layer needs to be processed at a high temperature above 450 °C. Such extreme processing conditions will limit the future development of perovskite solar cells, especially in terms of device flexibility. Therefore, it is very important to explore ways to prepare high-performance perovskite solar cells at low temperature.

Patent CN106384784A and patent CN106299141A introduce a perovskite solar cell with a composite electron transport layer structure and its manufacturing method. During the preparation process, a dense layer of _SnO2 is spin-coated on the conductive glass layer, and then calcined in a muffle furnace at 180°C 1h, compared with the N-type metal oxide molding temperature of 400 ° C, has been reduced, but the energy consumption is still high, which is not conducive to commercialization. Patent CN106449982A introduces a perovskite solar cell with chromium oxide as the electron transport layer and its preparation method. In the preparation process, the first electron transport layer is spin-coated, and then thermally evaporated or sputtered with chromium oxide for the second electron transport. layer, although the preparation process can reach below 150°C, it still consumes a lot of energy and the steps are cumbersome. Patent CN106449988A introduces a perovskite solar cell with an ultra-thin electron transport layer structure. During the preparation process, the electron transport layer adopts the dip coating method to immerse the FTO glass in the prepared titanium tetrachloride aqueous solution, and the ambient temperature needs to be controlled At 70°C, it needs to be dried at 150°C afterwards, which requires harsh conditions and cumbersome steps. Patent CN106711333A introduces a preparation method of the gradient heterojunction electron transport layer of perovskite solar cells. Calcining at ℃ for 30min, the method has harsh conditions, the steps are rather cumbersome, and the calcination temperature is high.

The present invention adopts solvothermal method to prepare titanium dioxide nano-dispersion liquid, and _TiO2 nano-dispersion liquid is compounded with alcohol-soluble conjugated polymer, prepares conjugated polymer/ _TiO2 hybrid material, adopts spin-coating method to combine conjugated polymer finally The polymer/TiO ₂ hybrid material was spin-coated on the plasma-treated ITO glass substrate to form a conjugated polymer/TiO ₂ hybrid film, which was the electron transport layer. Compared with the reported methods, the method can realize the preparation of the electron transport layer of the perovskite solar cell at low temperature (≤100° C.), and the operation method is simple.

Contents of the invention

The technical problem to be solved by the present invention is to provide a low-temperature preparation of an electron transport layer for a perovskite solar cell and a preparation method thereof.

The present invention is realized through the following technical solutions:

A hybrid used for the electron transport layer of a perovskite solar cell, characterized in that it is a hybrid material formed of alcohol/water-soluble conjugated polymer and nano TiO ₂ .

Wherein, the conjugated polymer structural formula is as follows:

In the formula, R _a is a hydrogen atom, or a C ₁ to C ₁₂ saturated alkane or unsaturated hydrocarbon group; R _b is selected from propionate, methyl propionate or 3-propylamide-2-methyl propanesulfonate sodium ; X value is 0.00～0.99.

Wherein, the mass ratio of conjugated polymer to TiO ₂ is 1:100˜100:1.

A kind of alcohol/water-soluble conjugated polymer/TiO _Hybrid material film, its preparation method comprises the following steps:

(1) Synthesis of water/alcohol-soluble conjugated polymers:

In the reactor, add dibromofluorene monomer, diboronic acid ester of A1, dibromoide of A2, catalyst, ligand, weak base and solvent, and heat to 85-95°C under nitrogen atmosphere to react 12 After ~24h, add phenylboronic acid to react for 2~3h, and finally add bromobenzene and react for 2~3h. After the reaction is finished, pour the reaction solution into acidified deionized water for precipitation, filter and dry, and purify the product obtained by column chromatography, concentrate the purified product solution with a rotary evaporator, precipitate again, and filter. The product can be dried.

Further, the dibromofluorene monomer is selected from 2,7-dibromo-9,9-bis(propionyl)fluorene, 2,7-dibromo-9,9-bis(2-methyl-3-propane One or more of 2,7-dibromo-9,9-bis(3-propylamide-2-methylpropanesulfonate sodium)fluorene.

Further, A1 is a diboronic acid ester, and its structural formula is:

Wherein, R ₂ is a hydrogen atom, or a C ₁ -C ₁₂ saturated alkane or unsaturated hydrocarbon group.

Further, A2 is a dibromo compound, and its structural formula is:

Wherein, R ₂ is a hydrogen atom, or a C ₁ -C ₁₂ saturated alkane or unsaturated hydrocarbon group.

Further, the ratio of the total number of moles of the dibromofluorene monomer and the dibromo product of A2 to the number of moles of the diboronate product of A1 is 0.5:1˜1:1.5. The ratio of the dibromofluorene monomer to the dibromo product of A2 is 1:100-100:1.

Further, the catalyst is a palladium catalyst, selected from one or more of Pd(OAc) ₂ , PdCl ₂ (dppf) or Pd(PPh ₃ ) ₄ ; The total molar ratio of the acid ester and the dibromo of A2 is 0.001:1˜0.06:1.

Further, the ligand is selected from one or more of tricyclohexylphosphine fluoroborate, tripyrrolidinylphosphine, triphenylphosphine, tri-tert-butylphosphine, tricyclohexylphosphine or triethylenediamine; The molar ratio of the ligand to the catalyst is 1:1-12:1.

Further, the weak base is selected from tetramethyl ammonium hydroxide aqueous solution, tetraethyl ammonium hydroxide aqueous solution, tetrapropyl ammonium hydroxide aqueous solution, tetrabutyl ammonium hydroxide aqueous solution, tetrahexyl ammonium hydroxide aqueous solution with a mass fraction of 5% to 50%. One or more of ammonium aqueous solution, tetraoctyl ammonium hydroxide aqueous solution, potassium carbonate aqueous solution, sodium carbonate aqueous solution or potassium acetate aqueous solution; The ratio of the total moles of the three substances of the dibromo compound of A2 is 1:1 to 12:1.

Further, the solvent is toluene, xylene, dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), dimethylacetamide (DMAc), N-methylpyrrolidone (NMP) one or more of.

Further, the dosages of phenylboronic acid and bromobenzene are 0.5-1 of the total moles of the three substances of the dibromofluorene monomer, the diboronic ester product of A1, and the dibromo product of A2.

(2) Preparation of TiO _nano -dispersion:

Mix solvent S, titanate and an appropriate amount of acid in a beaker, and stir magnetically for 10-20 minutes to obtain solution A. Another solvent S and deionized water were mixed in a beaker to obtain solution B. Under the condition of magnetic stirring, the solution B was slowly added dropwise to the solution A, and the stirring was continued for 20-30 minutes after the dropwise addition to obtain a translucent TiO ₂ sol. Finally, pour the TiO ₂ sol into a stainless steel reaction kettle lined with polytetrafluoroethylene, seal the reaction kettle and put it in an oven at 140-160°C for 5-8 hours. After the reaction, cool to room temperature to obtain translucent TiO ₂ nano-dispersion, average particle size ≤ 150nm.

Further, the solvent S is selected from one or more of methanol, ethanol, ethylene glycol, propylene glycol, glycerol, isopropanol, butanol, pentanol and hexanol;

Further, the titanate is selected from tetraethyl titanate, tetrabutyl titanate, tetrapropyl titanate, tetraisopropyl titanate, tetraisooctyl titanate and tetra(octadecyl) titanate one or more of them;

Further, the acid is selected from one or more of glacial acetic acid, hydrochloric acid, sulfuric acid, nitric acid and carbonic acid;

Further, the volume ratio of acid to titanate used in solution A and solution B is 1:1 to 1:20; the volume ratio of acid to water is 1:1 to 1:5;

Further, the prepared TiO ₂ nanometer dispersion has a concentration of 3 mg/mL˜40 mg/mL.

(3) Preparation of conjugated polymer/ _TiO2 hybrid electron transport layer:

The TiO _nano -dispersion liquid prepared in step (2) is placed in a glass bottle after being filtered with a filter head. Then weigh the alcohol/water-soluble conjugated polymer prepared in step (1) and dissolve it in the solvent. After the polymer is completely dissolved, filter it with a filter head, and mix the filtrate with the _TiO2 nano-dispersion liquid, and the blended solution is ultrasonically treated After 10-15 minutes, a stable and translucent conjugated polymer/TiO ₂ hybrid dispersion was obtained. The prepared conjugated polymer/ _TiO2 hybrid dispersion was spin-coated on the plasma-treated glass substrate to obtain a conjugated polymer/ _TiO2 hybrid material film, and finally the hybrid film was heated at 100 °C Just dry in the oven.

Further, the mass ratio of conjugated polymer to _TiO2 is 1:100～100:1;

Further, the organic solvent is selected from one or more of methanol, ethanol, ethylene glycol, propylene glycol, glycerol, isopropanol, butanol, propylene glycol methyl ether and ethylene glycol methyl ether.

A perovskite solar cell device prepared from the above-mentioned conjugated polymer/ _TiO2 hybrid material, the structure of the perovskite solar cell device is a cathode layer, an electron transport layer, and a perovskite layer from bottom to top. The structure of active layer, hole transport layer and anode layer is as follows:

Ag hole transport layer MAPbI ₃ electron transport layer ITO glass

Wherein, the cathode layer is etched ITO glass or FTO glass.

Among them, the electron transport layer is a conjugated polymer/TiO ₂ hybrid material film.

Wherein, the perovskite photoactive layer is prepared in an air environment (air humidity is less than 40%) by a spin continuous solution deposition method.

Wherein, the hole transport layer is poly-3-hexylthiophene (P3HT) or thiophene derivatives or small molecules containing thiophene, homopolymers or copolymers of polytriphenylamine or triphenylamine derivatives or small molecules containing triphenylamine , homopolymer or copolymer of polycarbazole or carbazole derivatives or small molecules containing carbazole, spiro-OMeTAD, phthalocyanine compounds.

Wherein, the anode is evaporated silver, gold or aluminum.

The present invention has the following advantages and beneficial effects:

The present invention provides a method for preparing an alcohol/water-soluble conjugated polymer whose side chain contains carboxyl or sulfonic acid groups; and provides an electron transport layer for perovskite solar cells that can be prepared at low temperature (≤100°C) hybrid materials and their preparation methods.

Detailed ways

The present invention will now be further described in conjunction with specific examples, and the following examples are intended to illustrate the present invention rather than further limit the present invention.

Example 1:

Preparation of conjugated polymer poly[9,9-dioctylfluorene-co-9,9-bis(propionyl)fluorene]:

Add 0.2808g (0.6mmol) 2,7-dibromo-9,9-bis(propionyl)fluorene, 0.3852g (0.6mmol) 2,7- Bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-diyl)-9,9-dioctylfluorene, 0.004g (0.018mmol) Pd(OAc) ₂ , 0.0134g (0.12mmol) DABCO, 8mL aqueous tetraethylammonium hydroxide solution with a mass fraction of 25%, 5mL DMSO and 5mL toluene, stirred evenly, and heated to 90°C under nitrogen atmosphere for 12h. Then add 0.0732g (0.6mmol) phenylboronic acid to react for 3h, then add 0.0942g (0.6mmol) bromobenzene to react for 3h. After the reaction, the reaction solution was poured into 200 mL of acidified deionized water for precipitation, filtered and dried, and the product obtained was purified by column chromatography (the stationary phase was neutral alumina, and the mobile phase was THF), and finally obtained Yellow polymer containing 50% carboxylic acid fluorene structural units, yield 45%. The NMR diagram is shown in Figure 1, the NMR diagram of poly[9,9-dioctylfluorene-co-9,9-bis(propionyl)fluorene]. Through GPC analysis, the measured number average molecular weight is 19600, the weight average molecular weight is 35000, and the molecular weight distribution is 1.79.

Example 2:

Preparation of conjugated polymer poly[9,9-dihexylfluorene-co-9,9-bis(2-methyl-3-propionyl)fluorene]:

Add 0.2371g (0.48mmol) 2,7-dibromo-9,9-bis(2-methyl-3-propionyl)fluorene, 0.0588g ( 0.12mmol) 2,7-dibromo-9,9-dihexylfluorene, 0.3518g (0.6 mmol) 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxo Borane-diyl)-9,9-dihexylfluorene, 0.004g (0.018mmol) Pd(OAc) ₂ , 0.0134g (0.12mmol) DABCO, 8mL 25% tetraethylammonium hydroxide aqueous solution , 5mL DMSO and 5mL toluene, stirred evenly, and heated to 90°C under nitrogen atmosphere to react for 12h. After that, 0.0732 g (0.6 mmol) of phenylboronic acid was added for reaction for 3 h, and then 0.0942 g (0.6 mmol) of bromobenzene was added for reaction for 3 h. After the reaction, the reaction solution was poured into 200 mL of acidified deionized water for precipitation, filtered and dried, and the product obtained was purified by column chromatography (the stationary phase was neutral alumina, and the mobile phase was THF), and finally obtained A polymer containing 40% carboxylic acid fluorene structural units.

Example 3:

Preparation of conjugated polymer poly[9,9-dioctylfluorene-co-9,9-bis(2-methyl-3-propionyl)fluorene]:

Add 0.1778g (0.36mmol) 2,7-dibromo-9,9-bis(2-methyl-3-propionyl)fluorene, 0.1316g ( 0.24mmol) 2,7-dibromo-9,9-dioctylfluorene, 0.3852g (0.6 mmol) 2,7-bis(4,4,5,5-tetramethyl-1,3,2-di Oxaborane-diyl)-9,9-dioctylfluorene, 0.004g (0.018mmol) Pd(OAc) ₂ , 0.0134g (0.12mmol) DABCO, 8mL tetraethyl hydroxide with a mass fraction of 25% Aqueous ammonium solution, 5 mL DMSO and 5 mL toluene were stirred evenly, and heated to 90° C. for 12 h under nitrogen atmosphere. After that, 0.0732 g (0.6 mmol) of phenylboronic acid was added for reaction for 3 h, and then 0.0942 g (0.6 mmol) of bromobenzene was added for reaction for 3 h. After the reaction, the reaction solution was poured into 200 mL of acidified deionized water for precipitation, filtered and dried, and the product obtained was purified by column chromatography (the stationary phase was neutral alumina, and the mobile phase was THF), and finally obtained A polymer containing 30% carboxylic acid fluorene structural units.

Example 4:

The preparation of _TiO2 nanodispersion with content of 3mg/mL:

Titanium dioxide nano-dispersion was prepared by solvothermal method. Mix 25 mL of anhydrous isopropanol, 0.5 mL of tetrapropyl titanate and 0.05 mL of nitric acid in a 50 mL beaker at room temperature, and stir magnetically for 10 minutes to obtain solution A. Another 5 mL of anhydrous isopropanol and 0.15 mL of deionized water were mixed in a 10 mL beaker, and solution B was obtained after ultrasonic treatment for 5 min. The solution B was slowly added dropwise to the solution A under the condition of magnetic stirring, and the stirring was continued for 20 min after the dropwise addition to obtain a translucent TiO ₂ sol. Finally, pour the TiO ₂ sol into a stainless steel reaction kettle lined with polytetrafluoroethylene, seal the reaction kettle and put it in an oven at 150°C for 6 hours of reaction. After the reaction, cool to room temperature to obtain translucent TiO ₂ nano-dispersion liquid. Through the test of solid content, the content of _TiO2 in the dispersion liquid is 3mg/mL. Detected by a laser particle size analyzer, the average particle size is 71nm, and the particle size distribution is 0.258.

Example 5:

The preparation of _TiO2 nano-dispersion liquid with content of 30mg/mL:

Titanium dioxide nano-dispersion was prepared by solvothermal method. Mix 25 mL of anhydrous methanol, 4 mL of tetrabutyl titanate and 0.4 mL of glacial acetic acid in a 50 mL beaker at room temperature, and stir magnetically for 10 minutes to obtain solution A. Another 5 mL of anhydrous methanol and 1.3 mL of deionized water were mixed in a 10 mL beaker, and solution B was obtained after ultrasonic treatment for 5 min. The solution B was slowly added dropwise to the solution A under the condition of magnetic stirring, and the stirring was continued for 20 min after the dropwise addition to obtain a translucent TiO ₂ sol. Finally, pour the TiO ₂ sol into a stainless steel reaction kettle lined with polytetrafluoroethylene, seal the reaction kettle and put it in an oven at 150°C for 6 hours of reaction. After the reaction, cool to room temperature to obtain translucent TiO ₂ nano-dispersion liquid. Through the test of solid content, the content of _TiO2 in the dispersion liquid is 30mg/mL. Detected by a laser particle size analyzer, the average particle size is 49nm, and the particle size distribution is 0.246.

Embodiment 6:

Content is the preparation of the TiO _nano- dispersion liquid of 40mg/mL:

Titanium dioxide nano-dispersion was prepared by solvothermal method. Mix 25 mL of absolute ethanol, 6 mL of tetraethyl titanate and 0.6 mL of hydrochloric acid in a 50 mL beaker at room temperature, and stir magnetically for 10 minutes to obtain solution A. Another 5 mL of absolute ethanol and 2 mL of deionized water were mixed in a 10 mL beaker, and solution B was obtained after ultrasonic treatment for 5 min. The solution B was slowly added dropwise to the solution A under the condition of magnetic stirring, and the stirring was continued for 20 min after the dropwise addition to obtain a translucent TiO ₂ sol. Finally, pour the TiO ₂ sol into a stainless steel reaction kettle lined with polytetrafluoroethylene, seal the reaction kettle and put it in an oven at 150°C for 6 hours of reaction. After the reaction, cool to room temperature to obtain translucent TiO ₂ nano-dispersion liquid. Through the test of solid content, the content of _TiO2 in the dispersion liquid is 40mg/mL. Detected by a laser particle size analyzer, the average particle size is 47nm, and the particle size distribution is 0.224.

Embodiment 7:

Preparation of Conjugated Polymer/ _TiO2 Hybrid Electron Transport Layer:

Conjugated polymer poly[9,9-dioctylfluorene-co-9,9-bis(propionyl)fluorene] (PF8COOH) prepared in Example 1 and TiO ₂ nano alcohol prepared in Example 5 The dispersion was used to prepare the electron transport layer.

Take ₂ mL of TiO nano-dispersion, filter it with a 0.45 μm filter head, and place it in a 10 mL glass bottle. Then weigh 6 mg of PF8COOH and dissolve it in 2 mL of THF solution. After the polymer is completely dissolved, filter it with a 0.45 μm filter head, and blend the filtrate with the TiO ₂ nano-dispersion liquid. A translucent PF8COOH/TiO ₂ dispersion. The prepared PF8COOH/ _TiO2 dispersion was spin-coated on the plasma-treated glass substrate at a speed of 4000rpm, and the spin-coating time was 30s to obtain a PF8COOH/ _TiO2 with a content of the conjugated polymer of 10% by mass _of TiO2 The hybrid material film was finally dried in an oven at 100°C.

Embodiment 8:

Prepare perovskite solar cells with the PF8COOH/ _TiO2 hybrid material prepared in embodiment 7:

A 5cm×5cm ITO conductive glass was etched and cut into a size of 1.25×1.25cm ² . Subsequently, the cut ITO conductive glass was ultrasonically cleaned with detergent, distilled water, acetone and isopropanol in sequence, and then placed in a vacuum drying oven for drying. After the ITO conductive glass is dried, the glass surface is treated with a plasma cleaning machine, and subsequent operations are performed after the treatment is completed. Dissolve PF8COOH in THF, add TiO ₂ nano-dispersion to prepare PF8COOH/TiO ₂ dispersion, then spin-coat the dispersion on the pre-treated ITO conductive glass surface, and then heat anneal at 100°C for 10 minutes. Further, the ITO glass substrate with the PF8COOH/TiO ₂ hybrid film was heated on a heating stage at 70°C, and then a 70°C PbI ₂ /DMF solution (550mg/mL) was spin-coated on the conjugated polymer/TiO ₂ surface, to obtain PbI ₂ film, the PbI ₂ film was annealed in air at 100°C for 1 min. After the _PbI2 film was cooled to room temperature, a small amount of isopropanol (IPA) solution was spin-coated on its surface to prewet the _PbI2 film. The MAI/IPA solution (70 mg/mL) was then spin-coated on the _PbI2 surface, after which the perovskite photoactive layer was annealed in a vacuum oven at 100 °C for 2 h. The polymer P3HT was formulated into a solution with a concentration of 20 mg/mL in advance, and the solvent was chloroform. Afterwards, the P3HT solution was spin-coated on the surface of the perovskite film MAPbI ₃ , and after the spin coating was completed, part of the P3HT film was wiped off with a cotton swab to expose the ITO electrode. Silver was used as the anode material, and silver was deposited on the surface of P3HT through a metal mask by thermal evaporation. During thermal evaporation, the vacuum degree was 1.5×10 ^-3 Pa, and the deposition rate was The deposition thickness is 200 nm. The effective area of the final perovskite solar cell device is 0.09 cm ² .

Its performance parameters are shown in Table 1, and the JV curve of the device is shown in Figure 2. The JV curve of the device when the polymer content in the PF8COOH/TiO ₂ hybrid film is different.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, and combinations made without departing from the spirit and principle of the present invention , simplification, all should be equivalent replacement methods, and are all included in the protection scope of the present invention.

Table 1 Solar cell performance with different polymer content in PF8COOH/TiO ₂ hybrid film

Description of drawings

Figure 1 NMR of poly[9,9-dioctylfluorene-co-9,9-bis(propionyl)fluorene]

Fig. ₂ JV curves of devices with different polymer content in PF8COOH/TiO2 hybrid film.

Claims (9)

1. A hybrid compound used for the electron transport layer of a perovskite solar cell, characterized in that: by alcohol/water-soluble conjugated polymer and nano TiO _2Hybrid material formed, wherein the conjugated polymer structural formula is: In the formula, R _a is a hydrogen atom, or C1～C12 saturated alkane or unsaturated hydrocarbon group; R _b is selected from propionate, methyl propionate or 3-propylamide-2-methylpropanesulfonate sodium; X The value is 0.00-0.99; the mass ratio of conjugated polymer to TiO ₂ is 1:100-100:1. 2. a kind of preparation method that is used for electron transport layer hybrid compound of perovskite solar cell according to claim 1, it is characterized in that comprising the following steps: (1) In a four-necked round-bottomed flask equipped with a magnet and a thermometer, add dibromofluorene monomers, diboronic acid esters of A1, dibromos of A2, catalysts, ligands, weak bases and solvents, in Under nitrogen atmosphere, heat to 85-95°C, react for 12-24 hours, add phenylboronic acid to react for 2-3 hours, finally add bromobenzene, react for 2-3 hours. After the reaction, the reaction solution is poured into acidified deionized water for precipitation, filtered and dried, and the obtained product is purified by column chromatography, precipitated again, filtered and dried; (2) Mix solvent S, titanate and appropriate amount of acid in a beaker at room temperature, and stir magnetically for 10-20 minutes to obtain solution A. Another solvent S and deionized water were mixed in a beaker to obtain solution B. Under the condition of magnetic stirring, the solution B was slowly added dropwise to the solution A, and the stirring was continued for 20-30 minutes after the dropwise addition to obtain a translucent TiO ₂ sol. Finally, pour the TiO ₂ sol into a stainless steel reaction kettle lined with polytetrafluoroethylene, seal the reaction kettle and put it in an oven at 140-160°C for 5-8 hours. After the reaction, cool to room temperature to obtain translucent TiO ₂ nano-dispersion liquid, average particle size ≤ 150nm; (3) The TiO _nano -dispersion liquid prepared in step (2) is placed in a glass bottle after filtering with a filter head. Then weigh the alcohol/water-soluble conjugated polymer prepared in step (1) and dissolve it in the solvent. After the polymer is completely dissolved, filter it with a filter head, and mix the filtrate with the _TiO2 nanometer dispersion, and the blended solution is ultrasonically treated. After 10-15 minutes, a stable and translucent conjugated polymer/TiO ₂ hybrid dispersion was obtained. The prepared conjugated polymer/ _TiO2 hybrid dispersion was spin-coated on the plasma-treated glass substrate to obtain a conjugated polymer/ _TiO2 hybrid material film, and finally the hybrid film was heated at 100 °C Dry in oven. 3. a kind of preparation method that is used for electron transport layer hybrid of perovskite solar cell according to claim 2 is characterized in that: in the described step (1), dibromofluorene monomer is 2,7-di Bromo-9,9-bis(propionyl)fluorene, 2,7-dibromo-9,9-bis(2-methyl-3-propionyl)fluorene, 2,7-dibromo-9,9 -one or more of two (3-propylamide-2-sodium methylpropanesulfonate) fluorenes; the structural formula of the diboronic acid ester of A1 is: In the formula, _R2 is a hydrogen atom, or a _C1 - _C12 saturated alkane or unsaturated hydrocarbon group; the structural formula of the dibromo compound of A2 is: In the formula, R ₂ is a hydrogen atom, or a C ₁ -C ₁₂ saturated alkane or unsaturated hydrocarbon group. 4. a kind of preparation method that is used for electron transport layer hybrid material of perovskite solar cell according to claim 2 is characterized in that: in the described step (1), dibromofluorene monomer and A2 dibromine The ratio of the total moles of the substitutes to the moles of the diboronic esters of A1 is 0.5:1˜1:1.5. The ratio of the dibromofluorene monomer to the dibromo product of A2 is 1:100-100:1. 5. a kind of preparation method that is used for electron transport layer hybrid material of perovskite solar cell according to claim 2 is characterized in that: in the described step (1), catalyst is palladium catalyst, is selected from Pd(OAc ) ₂ , one or more of PdCl ₂ (dppf) or Pd(PPh ₃ ) ₄ ; its molar number is the same as that of dibromofluorene monomer, diboronic ester of A1, and dibromo of A2 The ratio of the total moles is 0.001:1～0.6:1; in the step (1), the ligand is selected from tricyclohexylphosphine fluoroborate, tripyrrolidinylphosphine, triphenylphosphine, tri-tert-butyl One or more of base phosphine, tricyclohexyl phosphine or triethylenediamine; the molar ratio of ligand to catalyst is 1:1-12:1. 6. A kind of preparation method that is used for the electron transport layer hybrid material of perovskite solar cell according to claim 2, it is characterized in that: in described step (1), weak base is selected from mass fraction and is 5%～ 50% tetramethyl ammonium hydroxide aqueous solution, tetraethyl ammonium hydroxide aqueous solution, tetrapropyl ammonium hydroxide aqueous solution, tetrabutyl ammonium hydroxide aqueous solution, tetrahexyl ammonium hydroxide aqueous solution, tetraoctyl ammonium hydroxide aqueous solution, potassium carbonate One or more of the aqueous solution, sodium carbonate aqueous solution or potassium acetate aqueous solution; the moles of the weak base and the total moles of the three substances of the dibromofluorene monomer, the diboronic ester of A1, and the dibromo of A2 The ratio is 1:1～12:1; In the step (1), the solvent is selected from toluene, xylene, dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), di One or more of methylacetamide (DMAc) and N-methylpyrrolidone (NMP). 7. A kind of preparation method that is used for electron transport layer hybrid material of perovskite solar cell according to claim 2, it is characterized in that: in described step (2), solvent S is selected from methanol, ethanol, ethylene glycol One or more of alcohol, propylene glycol, glycerol, isopropanol, butanol, amyl alcohol and hexanol; in the step (2), the titanate is selected from tetraethyl titanate, tetraethyl titanate One or more of butyl ester, tetrapropyl titanate, tetraisopropyl titanate, tetraisooctyl titanate and tetra(octadecyl) titanate; the acid in the step (2) One or more selected from glacial acetic acid, hydrochloric acid, sulfuric acid, nitric acid and carbonic acid. 8. A kind of preparation method that is used for electron transport layer hybrid material of perovskite solar cell according to claim 2, it is characterized in that: in the described step (2), the volume ratio of acid and titanate is 1 :1～1:20; the volume ratio of acid to water is 1:1～1:5; the concentration of TiO ₂ nano dispersion is 3mg/mL～40mg/mL. 9. A kind of preparation method that is used for electron transport layer hybrid material of perovskite solar cell according to claim 2, it is characterized in that: in described step (3), organic solvent is selected from methanol, ethanol, ethylene glycol One or more of alcohol, propylene glycol, glycerol, isopropanol, butanol, propylene glycol methyl ether and ethylene glycol methyl ether; the mass ratio of conjugated polymer to TiO ₂ is 100:1-1:100.